He said that, in one college where he taught, three colleagues in the carpentry department all had time off for stress-related illness.
The main problems identified by Smith are the lack of rigour in national vocational qualifications and the fact that few students had chosen to study crafts of their own volition.
Describing the job as his "definition of hell", he added that none of his pupils had "the tiniest interest" in construction, turned up hours late for lessons and then passed the time talking incessantly and making calls on their mobile phones.
There are widespread fears about the quantity of skilled labour in the construction industry. Smith's observations will undoubtedly create concerns about its quality as well.